Together with the notion of secrecy, the core of Shi'i esotericism gravitates around the ẓāhir/bāṭin dualism. This dialectical relationship between the visible and the hidden, which has been inherited from Late Antiquity, buttresses the main doctrines of esoteric Shi'ism which include a dualistic worldview, doctrines of emanation, the contrast between the people of knowledge and of ignorance, the soterial nature of knowledge and of the Guide who possesses it, the two levels of the Scriptures, the need for hermeneutics, and initiatory knowledge and practices. It is true that the birthplace of Shi'ism was Iraq, which had been the central province of the Sassanid Persian Empire until the advent of Islam. This region and its main cities were home to the many intellectual and spiritual traditions of Late Antiquity, including various Jewish, Christian, Judeo-Christian, Mazdean, Manichean, Neoplatonic and Gnostic movements, with these traditions living on for several centuries after the advent of the religion of the Arabs. The articles in this collection, written by recognised scholars in the field, are divided into three sections covering a very wide period of time: the "prehistory" of these doctrines before Islam, early esoteric Shi'ism and its developments in both Shi'i and non-Shi'i Sufism, occult sciences and philosophy.